Improved composition for filling fire-proof safes



1OO. COMPOSITIONS,

cleanest-Leer.adamant-n,

COATING 0R PLASTIC.

UNITED STATES PATENT OFFICE.

WALTER K. MARVIN, OF NEW YORK, N. Y.

IMPROVED COMPOSITION FOR FILLING FIRE-PROOF SAFES.

Specification forming part of Letters Patent; No. 40,800, dated December 1, 1863.

proof doors. The desiderata of fire-proof safes,

of otherwise ordinary or suitable construction, are that the filling used between their outer and inner shells andwit-hin the inner and outer walls of the door, while a good non-conductor of heat, shall not be liable to corrode and de stroy the inner walls and other parts of the safe with which it comes in contact, nor communicate dampness to the interior of the safe, and thereby impair the binding of books, and damage paper and other valuables which safes are designed to contain and to protect. Gompounds heretofore in use fail in either of these particulars. Thus the filling most extensively used and consisting of pulverized calcined gypsum introduced into the cavities of the safe, mixed with water, and allowed to set into a solid consistence was liable to corrode the iron with which it came in contact and to impart dampness to the wood-work constituting the inner chest, thereby molding books, and impairing parchment and other property usually put in safes. Another objection to this filling consisted in the loss of its water by long exposure to the warm atmosphere of rooms in which safes are frequently kept, so that it became incapable, when exposed to fire, of producing sutficient vapor to preserve the contents of the safe. Clay and alum have also been employed for the purpose of lining safes;

but this compound could not be made permanently to fill the spaces of the safe, because, when subjected to even a moderate heat as compared with that which safes should be capable of sustaining, the filling would settle into the lower parts of the cavities, leaving the upper portion empty. To remedy this it was devised to intersperse the clay and alum compound with pieces of brick or other porous material forming cells which were to prevent the rang; ,ww raz g v1 filling from settling down; but this arrangement does not wholly accomplish the object for which it was intended, while it was comparatively expensive, as it required much time and skill to properly adjust the bricks.

To remedy these defects in fire-proof safes is the object of my invention; and my invention consists in forming a new compound for filling safes, chests, and other fire-proof structures by combining calcined and powdered gypsum with alum when the latter is embedded into the former in such relative proportions as that the water of crystallization of the alum which may be evolved by heat shall supply the quantity requisite to set the plaster.

To enable others skilled in the art to make and use my invention, I shall now proceed to describe the manner in which the same may be carried into efiect.

I take calcined sum or laster-of- )aris and alum'l'n' tlfe proportions of about SIX parts of tmlel' to four parts of the latter, and intimately mix and incorporate the same. The alum I prefer to break into pieces varying in weight from one grain to half an ounce. I in; troduce this mixture or compound into the safe between the inner and outer shells, also fill the space within the door formed by the outer and inner plates thereof. The compound should be carefully packed, so as to produce a homogeneous mass throughout, and as densely as practicable. Before filling the safe, as described, care should be taken to pack hermetically the joints and to coat the surface of the iron exposed to contact with the compound with a composition such as will protect the iron from corrosion. I have found that soluble glass or liquid quartz a lied with a Brusli and'then heated forms a 11111 or Lglaze over Elie w oe surace w lcl Wl plish the purpose.

The advantages which my process or compound of filling possesses over those heretofore inusearemanifold. Theprincipal,however,are, first, absence from moisture or dampness while the safe is in use, the plaster being in a dry or calcined state within the walls of the safe; second, there is no tendency of the compound to settle when exposed to heat, because the water to be supplied is held by the alum in suspension throughout the whole mass of plaster, ready to be yielded whenever necessary to mix with the plaster and to set it, and, as it e ec-ua y accomtastiest were, to petrify it in position.

, fore no settling of the com pound. In other respects the new compound combines the qualities of the alum filling and the plaster-of-paris filling heretofore used.

I F heated to a temperature of about 212 emits its water of crystallization which,read1lycombimng with the surrounding plaster, produces a species of crystallization, whereby the plaswhere the alum was embedded in the mass of plaster. After the plaster is set, as described,

. higher temperature, say 400 Fahrenheit, the oombined water escapes and fills the cavities "plaster-of-paris or other materials-such as .slaked lime, drier, clay, &c.have been used 1 position I distinctly disclaim.

There is there- It will be understood that the alum when ter acquires solid consistence and becomes set. The plaster is then converted into a spongy mass containing cells which indicate the places the filling composition behaves like the old plaster filling-i e., when exposed to a still within the shells of the safes with vapor or steam, which resists their destruction by fire. I am aware that sulphate of iron mixed with or suggested as'a filling for safes. Such com- Having now fully described my improve-i? I ment and the manner in which the same is o {:1

may be carried into effect, I would observetha I do not wish to confine myself to the precise j proportions of ingredients hereinbefore dei scribed; but

I do claim as my invention- The herein-described compound for filling}; safes and other fire-proof structures, the same 7. consisting in the combination, with calcined and powdered gypsum, of alum in pieces embedded in and interspersed through the mass of plaster in such relative proportions as that; the water of crystallization of the alum which may be evolved by heat shall supply the quanf;-

tit y requisite of water to set the plaster, substantially as and for the purposes set forth.

In testimony whereof I have signed my name 1; I to this specification before two subscribing wit- DBSSES.

WALTER K. MARVIN.

Witnesses:

A. PoLLoK, JOHN S. HOLLINGSHEAD. 

